They used the same illustration for "dire wolf" as just plain "wolf". I don't know if that was intentional. Is a 5e dire wolf just a bigger wolf? It's fine if that's the case, but the wolf pictured in RickAJr's comment certainly looks more like what I'd expect a 'dire' wolf to look like. But maybe that's just old-school me.

Incidentally, the dire wolf in that post is a mini from Pathfinder Battles "Deep Cuts" line from WizKids, a company that also does official D&D minis. WizKids is scheduled to release another line of official D&D minis -- D&D Icons of the Realms, "Waterdeep Dragon Heist" line -- in September 2018. That line contains a dire wolf figure that (from what I can tell) looks a bit like a mix of both. No spikes, but definitely has it's hackles up.

Ideally, the idea is to not tell them a dire wolf is about to attack. Instead, use the description of the beast when introducing and have them roll a check for knowledge (that's what I mean by show - describe the scene - show it to them in their minds). I try to always do this when they first encounter a monster. I keep a list of all monsters encountered by the party in the dndbeyond campaign notes. When they come across the same monster later, I'll then state that it's a dire wolf. I really like 5th edition and everything about it builds upon the previous systems before it, but what I'm disappointed with is the monster manual's description. I'm always going back to my 3.5 edition book and pulling the description from there - I feel that while it might be difficult to reprint the monster manual with updated descriptions, the folks at dndbeyond could put those 3.5 edition descriptions back in - unlike a book, electronic page/space is free. I did a whole bunch for my own prep and shared, but quite frankly, I don't have the time. The above chart could/should be done for all monsters in the electronic version here on dndbeyond.

The Creature rolls a d20 and adds the "+5" onto the value to determine a hit, e.g.: it rolls a 13, add 5 = 18 (so its hits any target with armour class 18 or less).

If it hits, you determine the done damage by rolling "2d6 +3" (the "10" is an average value if you wont do dice rolls, bc the damage range is 5-15), e.g.:1. roll 42. roll 5. 4 + 5= 9 + 3 = 12.So the wolf does 12 damage in total.

The wolf can attack anything within 5ft of it. After you roll for the attack you add 5 to the rolled number. If the new number is higher than the ac of the creature it attacked you roll two 6-sided die then add 3 to the number rolled. The number you get is the amount of damage taken.